1. Field of the Invention
The present invention relates to an apparatus for recovering a carrier from a photoreceptor belt in a liquid electrophotographic printer.
2. Description of the Related Art
An electrophotographic printer such as a laser color printer develops and prints an electrostatic latent image using a developer liquid in which a powdered toner is mixed with a liquid carrier. Referring to FIG. 1, a conventional liquid electrophotographic printer includes a printing unit 10 for transmitting an image to a sheet 1 by a photoreceptor belt 14 as a photosensitive medium, and a carrier recovery apparatus 20 for removing a liquid carrier from the photoreceptor belt 14 and recovering the same.
The printing unit 10 includes a photoreceptor belt 14 mounted on and circulated by a plurality of guide rollers 11, 12 and 13, laser scanning units 18a, 18b, 18c and 18d for forming a latent electrostatic image on the photoreceptor belt 14, and development devices 15a, 15b, 15c and 15d for developing the latent electrostatic image by applying a developer liquid having a carrier mixed with a toner, and a transfer roller 16 for transferring the developed image onto a sheet 1.
Referring to FIG. 2 showing a detailed diagram of the carrier recovery apparatus 20, first, in a manifold 21, there are provided a drying roller 22 for absorbing the liquid carrier from a photoreceptor belt 14 while rotating in contact with the photoreceptor belt 14, and at least one heating roller 23 for heating the drying roller in contact therewith and evaporating the absorbed carrier. Some of the evaporated gas carrier is condensed on the inner surface of the manifold 21 into liquid form and then induced to a cartridge 26 through a first recovery tube 25.
Also, the uncondensed gas carrier of the manifold 21 is induced to a condenser 28 along a supply line 27 by the driving of a supply fan 29. Since a liquid condensed carrier 28a is contained in the condenser 28, the induced gas carrier is liquefied by heat exchange with the condensed carrier 28a. If the surface level of the carrier is raised by the condensation of the gas carrier, some of the condensed carrier is recovered in the cartridge 26 through a second recovery tube 31.
Also, the gas carrier which is not condensed in the condenser 28 is filtered by a filter 30 while it is exhausted to the outside together with the air. Reference numeral 19 represents an exhaust line leading to the outside via the filter 30, for removing moisture in the printing unit 10, reference numerals 32 and 33 represent a drain line and a moisture separation container, respectively, for separating moisture from the liquid carrier 28a stored in the condenser 28.
In the conventional carrier recovery apparatus, the gas carrier which is not condensed in the condenser 28 is filtered by the filter 30. Therefore, if the filtering capacity of the filter 30 is lowered, some of the gas carrier may be effused to the outside. The effused carrier causes environmental pollution. Therefore, it is necessary to suppress the efflux of the carrier.